/**
 * Copyright (C) 2011-2015 The XDocReport Team <xdocreport@googlegroups.com>
 *
 * All rights reserved.
 *
 * Permission is hereby granted, free  of charge, to any person obtaining
 * a  copy  of this  software  and  associated  documentation files  (the
 * "Software"), to  deal in  the Software without  restriction, including
 * without limitation  the rights to  use, copy, modify,  merge, publish,
 * distribute,  sublicense, and/or sell  copies of  the Software,  and to
 * permit persons to whom the Software  is furnished to do so, subject to
 * the following conditions:
 *
 * The  above  copyright  notice  and  this permission  notice  shall  be
 * included in all copies or substantial portions of the Software.
 *
 * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
 * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
 * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package fr.opensagres.odfdom.converter.core.utils;

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.CharArrayWriter;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Iterator;
import java.util.List;

//import org.apache.commons.io.output.ByteArrayOutputStream;

/**
 * General IO stream manipulation utilities.
 * <p>
 * This class provides static utility methods for input/output operations.
 * <ul>
 * <li>closeQuietly - these methods close a stream ignoring nulls and exceptions
 * <li>toXxx/read - these methods read data from a stream
 * <li>write - these methods write data to a stream
 * <li>copy - these methods copy all the data from one stream to another
 * <li>contentEquals - these methods compare the content of two streams
 * </ul>
 * <p>
 * The byte-to-char methods and char-to-byte methods involve a conversion step. Two methods are provided in each case,
 * one that uses the platform default encoding and the other which allows you to specify an encoding. You are encouraged
 * to always specify an encoding because relying on the platform default can lead to unexpected results, for example
 * when moving from development to production.
 * <p>
 * All the methods in this class that read a stream are buffered internally. This means that there is no cause to use a
 * <code>BufferedInputStream</code> or <code>BufferedReader</code>. The default buffer size of 4K has been shown to be
 * efficient in tests.
 * <p>
 * Wherever possible, the methods in this class do <em>not</em> flush or close the stream. This is to avoid making
 * non-portable assumptions about the streams' origin and further use. Thus the caller is still responsible for closing
 * streams after use.
 * <p>
 * Origin of code: Excalibur.
 * 
 * @author Peter Donald
 * @author Jeff Turner
 * @author Matthew Hawthorne
 * @author Stephen Colebourne
 * @author Gareth Davis
 * @author Ian Springer
 * @author Niall Pemberton
 * @author Sandy McArthur
 * @version $Id: IOUtils.java 481854 2006-12-03 18:30:07Z scolebourne $
 */
public class IOUtils
{
    /**
     * Logger for this class
     */
    //private static final Logger logger = LogUtils.getLogger( IOUtils.class.getName() );

    // NOTE: This class is focussed on InputStream, OutputStream, Reader and
    // Writer. Each method should take at least one of these as a parameter,
    // or return one of them.

    /**
     * The Unix directory separator character.
     */
    public static final char DIR_SEPARATOR_UNIX = '/';

    /**
     * The Windows directory separator character.
     */
    public static final char DIR_SEPARATOR_WINDOWS = '\\';

    /**
     * The system directory separator character.
     */
    public static final char DIR_SEPARATOR = File.separatorChar;

    /**
     * The Unix line separator string.
     */
    public static final String LINE_SEPARATOR_UNIX = "\n";

    /**
     * The Windows line separator string.
     */
    public static final String LINE_SEPARATOR_WINDOWS = "\r\n";

    /**
     * The system line separator string.
     */
    public static final String LINE_SEPARATOR;
    static
    {
        // avoid security issues
        StringWriter buf = new StringWriter( 4 );
        PrintWriter out = new PrintWriter( buf );
        out.println();
        LINE_SEPARATOR = buf.toString();
    }

    /**
     * The default buffer size to use.
     */
    private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;

    /**
     * Instances should NOT be constructed in standard programming.
     */
    public IOUtils()
    {
        super();
    }

    // -----------------------------------------------------------------------
    /**
     * Unconditionally close an <code>Reader</code>.
     * <p>
     * Equivalent to {@link Reader#close()}, except any exceptions will be ignored. This is typically used in finally
     * blocks.
     * 
     * @param input the Reader to close, may be null or already closed
     */
    public static void closeQuietly( Reader input )
    {
        try
        {
            if ( input != null )
            {
                input.close();
            }
        }
        catch ( IOException ioe )
        {
            //logger.warning( "Reader - exception ignored - exception: " + ioe ); //$NON-NLS-1$

            // ignore
        }
    }

    /**
     * Unconditionally close a <code>Writer</code>.
     * <p>
     * Equivalent to {@link Writer#close()}, except any exceptions will be ignored. This is typically used in finally
     * blocks.
     * 
     * @param output the Writer to close, may be null or already closed
     */
    public static void closeQuietly( Writer output )
    {
        try
        {
            if ( output != null )
            {
                output.close();
            }
        }
        catch ( IOException ioe )
        {
            //logger.warning( "Writer - exception ignored - exception: " + ioe ); //$NON-NLS-1$

            // ignore
        }
    }

    /**
     * Unconditionally close an <code>InputStream</code>.
     * <p>
     * Equivalent to {@link InputStream#close()}, except any exceptions will be ignored. This is typically used in
     * finally blocks.
     * 
     * @param input the InputStream to close, may be null or already closed
     */
    public static void closeQuietly( InputStream input )
    {
        try
        {
            if ( input != null )
            {
                input.close();
            }
        }
        catch ( IOException ioe )
        {
            //logger.warning( "InputStream - exception ignored - exception: " + ioe ); //$NON-NLS-1$

            // ignore
        }
    }

    /**
     * Unconditionally close an <code>OutputStream</code>.
     * <p>
     * Equivalent to {@link OutputStream#close()}, except any exceptions will be ignored. This is typically used in
     * finally blocks.
     * 
     * @param output the OutputStream to close, may be null or already closed
     */
    public static void closeQuietly( OutputStream output )
    {
        try
        {
            if ( output != null )
            {
                output.close();
            }
        }
        catch ( IOException ioe )
        {
            //logger.warning( "OutputStream - exception ignored - exception: " + ioe ); //$NON-NLS-1$

            // ignore
        }
    }

    // read toByteArray
    // -----------------------------------------------------------------------
    /**
     * Get the contents of an <code>InputStream</code> as a <code>byte[]</code>.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * 
     * @param input the <code>InputStream</code> to read from
     * @return the requested byte array
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     */
    public static byte[] toByteArray( InputStream input )
        throws IOException
    {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        copy( input, output );
        return output.toByteArray();
    }

    /**
     * Get the contents of a <code>Reader</code> as a <code>byte[]</code> using the default character encoding of the
     * platform.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedReader</code>.
     * 
     * @param input the <code>Reader</code> to read from
     * @return the requested byte array
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     */
    public static byte[] toByteArray( Reader input )
        throws IOException
    {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        copy( input, output );
        return output.toByteArray();
    }

    /**
     * Get the contents of a <code>Reader</code> as a <code>byte[]</code> using the specified character encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedReader</code>.
     * 
     * @param input the <code>Reader</code> to read from
     * @param encoding the encoding to use, null means platform default
     * @return the requested byte array
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static byte[] toByteArray( Reader input, String encoding )
        throws IOException
    {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        copy( input, output, encoding );
        return output.toByteArray();
    }

    /**
     * Get the contents of a <code>String</code> as a <code>byte[]</code> using the default character encoding of the
     * platform.
     * <p>
     * This is the same as {@link String#getBytes()}.
     * 
     * @param input the <code>String</code> to convert
     * @return the requested byte array
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs (never occurs)
     * @deprecated Use {@link String#getBytes()}
     */
    public static byte[] toByteArray( String input )
        throws IOException
    {
        return input.getBytes();
    }

    // read char[]
    // -----------------------------------------------------------------------
    /**
     * Get the contents of an <code>InputStream</code> as a character array using the default character encoding of the
     * platform.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * 
     * @param is the <code>InputStream</code> to read from
     * @return the requested character array
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static char[] toCharArray( InputStream is )
        throws IOException
    {
        CharArrayWriter output = new CharArrayWriter();
        copy( is, output );
        return output.toCharArray();
    }

    /**
     * Get the contents of an <code>InputStream</code> as a character array using the specified character encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * 
     * @param is the <code>InputStream</code> to read from
     * @param encoding the encoding to use, null means platform default
     * @return the requested character array
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static char[] toCharArray( InputStream is, String encoding )
        throws IOException
    {
        CharArrayWriter output = new CharArrayWriter();
        copy( is, output, encoding );
        return output.toCharArray();
    }

    /**
     * Get the contents of a <code>Reader</code> as a character array.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedReader</code>.
     * 
     * @param input the <code>Reader</code> to read from
     * @return the requested character array
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static char[] toCharArray( Reader input )
        throws IOException
    {
        CharArrayWriter sw = new CharArrayWriter();
        copy( input, sw );
        return sw.toCharArray();
    }

    // read toString
    // -----------------------------------------------------------------------
    /**
     * Get the contents of an <code>InputStream</code> as a String using the default character encoding of the platform.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * 
     * @param input the <code>InputStream</code> to read from
     * @return the requested String
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     */
    public static String toString( InputStream input )
        throws IOException
    {
        StringWriter sw = new StringWriter();
        copy( input, sw );
        return sw.toString();
    }

    /**
     * Get the contents of an <code>InputStream</code> as a String using the specified character encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * 
     * @param input the <code>InputStream</code> to read from
     * @param encoding the encoding to use, null means platform default
     * @return the requested String
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     */
    public static String toString( InputStream input, String encoding )
        throws IOException
    {
        StringWriter sw = new StringWriter();
        copy( input, sw, encoding );
        return sw.toString();
    }

    /**
     * Get the contents of a <code>Reader</code> as a String.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedReader</code>.
     * 
     * @param input the <code>Reader</code> to read from
     * @return the requested String
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     */
    public static String toString( Reader input )
        throws IOException
    {
        StringWriter sw = new StringWriter();
        copy( input, sw );
        return sw.toString();
    }

    /**
     * Get the contents of a <code>byte[]</code> as a String using the default character encoding of the platform.
     * 
     * @param input the byte array to read from
     * @return the requested String
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs (never occurs)
     * @deprecated Use {@link String#String(byte[])}
     */
    public static String toString( byte[] input )
        throws IOException
    {
        return new String( input );
    }

    /**
     * Get the contents of a <code>byte[]</code> as a String using the specified character encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * 
     * @param input the byte array to read from
     * @param encoding the encoding to use, null means platform default
     * @return the requested String
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs (never occurs)
     * @deprecated Use {@link String#String(byte[],String)}
     */
    public static String toString( byte[] input, String encoding )
        throws IOException
    {
        if ( encoding == null )
        {
            return new String( input );
        }
        else
        {
            return new String( input, encoding );
        }
    }

    // readLines
    // -----------------------------------------------------------------------
    /**
     * Get the contents of an <code>InputStream</code> as a list of Strings, one entry per line, using the default
     * character encoding of the platform.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * 
     * @param input the <code>InputStream</code> to read from, not null
     * @return the list of Strings, never null
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static List<String> readLines( InputStream input )
        throws IOException
    {
        InputStreamReader reader = new InputStreamReader( input );
        return readLines( reader );
    }

    /**
     * Get the contents of an <code>InputStream</code> as a list of Strings, one entry per line, using the specified
     * character encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * 
     * @param input the <code>InputStream</code> to read from, not null
     * @param encoding the encoding to use, null means platform default
     * @return the list of Strings, never null
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static List<String> readLines( InputStream input, String encoding )
        throws IOException
    {
        if ( encoding == null )
        {
            return readLines( input );
        }
        else
        {
            InputStreamReader reader = new InputStreamReader( input, encoding );
            return readLines( reader );
        }
    }

    /**
     * Get the contents of a <code>Reader</code> as a list of Strings, one entry per line.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedReader</code>.
     * 
     * @param input the <code>Reader</code> to read from, not null
     * @return the list of Strings, never null
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static List<String> readLines( Reader input )
        throws IOException
    {
        BufferedReader reader = new BufferedReader( input );
        List<String> list = new ArrayList<String>();
        String line = reader.readLine();
        while ( line != null )
        {
            list.add( line );
            line = reader.readLine();
        }
        return list;
    }

    // lineIterator
    // -----------------------------------------------------------------------
    /**
     * Return an Iterator for the lines in a <code>Reader</code>.
     * <p>
     * <code>LineIterator</code> holds a reference to the open <code>Reader</code> specified here. When you have
     * finished with the iterator you should close the reader to free internal resources. This can be done by closing
     * the reader directly, or by calling {@link LineIterator#close()} or
     * {@link LineIterator#closeQuietly(LineIterator)}.
     * <p>
     * The recommended usage pattern is:
     * 
     * <pre>
     * try
     * {
     *     LineIterator it = IOUtils.lineIterator( reader );
     *     while ( it.hasNext() )
     *     {
     *         String line = it.nextLine();
     *         // / do something with line
     *     }
     * }
     * finally
     * {
     *     IOUtils.closeQuietly( reader );
     * }
     * </pre>
     * 
     * @param reader the <code>Reader</code> to read from, not null
     * @return an Iterator of the lines in the reader, never null
     * @throws IllegalArgumentException if the reader is null
     * @since Commons IO 1.2
//     */
//    public static LineIterator lineIterator( Reader reader )
//    {
//        return new LineIterator( reader );
//    }

    /**
     * Return an Iterator for the lines in an <code>InputStream</code>, using the character encoding specified (or
     * default encoding if null).
     * <p>
     * <code>LineIterator</code> holds a reference to the open <code>InputStream</code> specified here. When you have
     * finished with the iterator you should close the stream to free internal resources. This can be done by closing
     * the stream directly, or by calling {@link LineIterator#close()} or
     * {@link LineIterator#closeQuietly(LineIterator)}.
     * <p>
     * The recommended usage pattern is:
     * 
     * <pre>
     * try
     * {
     *     LineIterator it = IOUtils.lineIterator( stream, &quot;UTF-8&quot; );
     *     while ( it.hasNext() )
     *     {
     *         String line = it.nextLine();
     *         // / do something with line
     *     }
     * }
     * finally
     * {
     *     IOUtils.closeQuietly( stream );
     * }
     * </pre>
     * 
     * @param input the <code>InputStream</code> to read from, not null
     * @param encoding the encoding to use, null means platform default
     * @return an Iterator of the lines in the reader, never null
     * @throws IllegalArgumentException if the input is null
     * @throws IOException if an I/O error occurs, such as if the encoding is invalid
     * @since Commons IO 1.2
     */
//    public static LineIterator lineIterator( InputStream input, String encoding )
//        throws IOException
//    {
//        Reader reader = null;
//        if ( encoding == null )
//        {
//            reader = new InputStreamReader( input );
//        }
//        else
//        {
//            reader = new InputStreamReader( input, encoding );
//        }
//        return new LineIterator( reader );
//    }

    // -----------------------------------------------------------------------
    /**
     * Convert the specified string to an input stream, encoded as bytes using the default character encoding of the
     * platform.
     * 
     * @param input the string to convert
     * @return an input stream
     * @since Commons IO 1.1
     */
    public static InputStream toInputStream( String input )
    {
        byte[] bytes = input.getBytes();
        return new ByteArrayInputStream( bytes );
    }

    /**
     * Convert the specified string to an input stream, encoded as bytes using the specified character encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * 
     * @param input the string to convert
     * @param encoding the encoding to use, null means platform default
     * @throws IOException if the encoding is invalid
     * @return an input stream
     * @since Commons IO 1.1
     */
    public static InputStream toInputStream( String input, String encoding )
        throws IOException
    {
        byte[] bytes = encoding != null ? input.getBytes( encoding ) : input.getBytes();
        return new ByteArrayInputStream( bytes );
    }

    // write byte[]
    // -----------------------------------------------------------------------
    /**
     * Writes bytes from a <code>byte[]</code> to an <code>OutputStream</code>.
     * 
     * @param data the byte array to write, do not modify during output, null ignored
     * @param output the <code>OutputStream</code> to write to
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( byte[] data, OutputStream output )
        throws IOException
    {
        if ( data != null )
        {
            output.write( data );
        }
    }

    /**
     * Writes bytes from a <code>byte[]</code> to chars on a <code>Writer</code> using the default character encoding of
     * the platform.
     * <p>
     * This method uses {@link String#String(byte[])}.
     * 
     * @param data the byte array to write, do not modify during output, null ignored
     * @param output the <code>Writer</code> to write to
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( byte[] data, Writer output )
        throws IOException
    {
        if ( data != null )
        {
            output.write( new String( data ) );
        }
    }

    /**
     * Writes bytes from a <code>byte[]</code> to chars on a <code>Writer</code> using the specified character encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method uses {@link String#String(byte[], String)}.
     * 
     * @param data the byte array to write, do not modify during output, null ignored
     * @param output the <code>Writer</code> to write to
     * @param encoding the encoding to use, null means platform default
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( byte[] data, Writer output, String encoding )
        throws IOException
    {
        if ( data != null )
        {
            if ( encoding == null )
            {
                write( data, output );
            }
            else
            {
                output.write( new String( data, encoding ) );
            }
        }
    }

    // write char[]
    // -----------------------------------------------------------------------
    /**
     * Writes chars from a <code>char[]</code> to a <code>Writer</code> using the default character encoding of the
     * platform.
     * 
     * @param data the char array to write, do not modify during output, null ignored
     * @param output the <code>Writer</code> to write to
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( char[] data, Writer output )
        throws IOException
    {
        if ( data != null )
        {
            output.write( data );
        }
    }

    /**
     * Writes chars from a <code>char[]</code> to bytes on an <code>OutputStream</code>.
     * <p>
     * This method uses {@link String#String(char[])} and {@link String#getBytes()}.
     * 
     * @param data the char array to write, do not modify during output, null ignored
     * @param output the <code>OutputStream</code> to write to
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( char[] data, OutputStream output )
        throws IOException
    {
        if ( data != null )
        {
            output.write( new String( data ).getBytes() );
        }
    }

    /**
     * Writes chars from a <code>char[]</code> to bytes on an <code>OutputStream</code> using the specified character
     * encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method uses {@link String#String(char[])} and {@link String#getBytes(String)}.
     * 
     * @param data the char array to write, do not modify during output, null ignored
     * @param output the <code>OutputStream</code> to write to
     * @param encoding the encoding to use, null means platform default
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( char[] data, OutputStream output, String encoding )
        throws IOException
    {
        if ( data != null )
        {
            if ( encoding == null )
            {
                write( data, output );
            }
            else
            {
                output.write( new String( data ).getBytes( encoding ) );
            }
        }
    }

    // write String
    // -----------------------------------------------------------------------
    /**
     * Writes chars from a <code>String</code> to a <code>Writer</code>.
     * 
     * @param data the <code>String</code> to write, null ignored
     * @param output the <code>Writer</code> to write to
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( String data, Writer output )
        throws IOException
    {
        if ( data != null )
        {
            output.write( data );
        }
    }

    /**
     * Writes chars from a <code>String</code> to bytes on an <code>OutputStream</code> using the default character
     * encoding of the platform.
     * <p>
     * This method uses {@link String#getBytes()}.
     * 
     * @param data the <code>String</code> to write, null ignored
     * @param output the <code>OutputStream</code> to write to
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( String data, OutputStream output )
        throws IOException
    {
        if ( data != null )
        {
            output.write( data.getBytes() );
        }
    }

    /**
     * Writes chars from a <code>String</code> to bytes on an <code>OutputStream</code> using the specified character
     * encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method uses {@link String#getBytes(String)}.
     * 
     * @param data the <code>String</code> to write, null ignored
     * @param output the <code>OutputStream</code> to write to
     * @param encoding the encoding to use, null means platform default
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( String data, OutputStream output, String encoding )
        throws IOException
    {
        if ( data != null )
        {
            if ( encoding == null )
            {
                write( data, output );
            }
            else
            {
                output.write( data.getBytes( encoding ) );
            }
        }
    }

    // write StringBuffer
    // -----------------------------------------------------------------------
    /**
     * Writes chars from a <code>StringBuffer</code> to a <code>Writer</code>.
     * 
     * @param data the <code>StringBuffer</code> to write, null ignored
     * @param output the <code>Writer</code> to write to
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( StringBuffer data, Writer output )
        throws IOException
    {
        if ( data != null )
        {
            output.write( data.toString() );
        }
    }

    /**
     * Writes chars from a <code>StringBuffer</code> to bytes on an <code>OutputStream</code> using the default
     * character encoding of the platform.
     * <p>
     * This method uses {@link String#getBytes()}.
     * 
     * @param data the <code>StringBuffer</code> to write, null ignored
     * @param output the <code>OutputStream</code> to write to
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( StringBuffer data, OutputStream output )
        throws IOException
    {
        if ( data != null )
        {
            output.write( data.toString().getBytes() );
        }
    }

    /**
     * Writes chars from a <code>StringBuffer</code> to bytes on an <code>OutputStream</code> using the specified
     * character encoding.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method uses {@link String#getBytes(String)}.
     * 
     * @param data the <code>StringBuffer</code> to write, null ignored
     * @param output the <code>OutputStream</code> to write to
     * @param encoding the encoding to use, null means platform default
     * @throws NullPointerException if output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void write( StringBuffer data, OutputStream output, String encoding )
        throws IOException
    {
        if ( data != null )
        {
            if ( encoding == null )
            {
                write( data, output );
            }
            else
            {
                output.write( data.toString().getBytes( encoding ) );
            }
        }
    }

    // writeLines
    // -----------------------------------------------------------------------
    /**
     * Writes the <code>toString()</code> value of each item in a collection to an <code>OutputStream</code> line by
     * line, using the default character encoding of the platform and the specified line ending.
     * 
     * @param lines the lines to write, null entries produce blank lines
     * @param lineEnding the line separator to use, null is system default
     * @param output the <code>OutputStream</code> to write to, not null, not closed
     * @throws NullPointerException if the output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void writeLines( Collection<String> lines, String lineEnding, OutputStream output )
        throws IOException
    {
        if ( lines == null )
        {
            return;
        }
        if ( lineEnding == null )
        {
            lineEnding = LINE_SEPARATOR;
        }
        for ( Iterator<String> it = lines.iterator(); it.hasNext(); )
        {
            String line = it.next();
            if ( line != null )
            {
                output.write( line.getBytes() );
            }
            output.write( lineEnding.getBytes() );
        }
    }

    /**
     * Writes the <code>toString()</code> value of each item in a collection to an <code>OutputStream</code> line by
     * line, using the specified character encoding and the specified line ending.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * 
     * @param lines the lines to write, null entries produce blank lines
     * @param lineEnding the line separator to use, null is system default
     * @param output the <code>OutputStream</code> to write to, not null, not closed
     * @param encoding the encoding to use, null means platform default
     * @throws NullPointerException if the output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void writeLines( Collection<String> lines, String lineEnding, OutputStream output, String encoding )
        throws IOException
    {
        if ( encoding == null )
        {
            writeLines( lines, lineEnding, output );
        }
        else
        {
            if ( lines == null )
            {
                return;
            }
            if ( lineEnding == null )
            {
                lineEnding = LINE_SEPARATOR;
            }
            for ( Iterator<String> it = lines.iterator(); it.hasNext(); )
            {
                Object line = it.next();
                if ( line != null )
                {
                    output.write( line.toString().getBytes( encoding ) );
                }
                output.write( lineEnding.getBytes( encoding ) );
            }
        }
    }

    /**
     * Writes the <code>toString()</code> value of each item in a collection to a <code>Writer</code> line by line,
     * using the specified line ending.
     * 
     * @param lines the lines to write, null entries produce blank lines
     * @param lineEnding the line separator to use, null is system default
     * @param writer the <code>Writer</code> to write to, not null, not closed
     * @throws NullPointerException if the input is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void writeLines( Collection<String> lines, String lineEnding, Writer writer )
        throws IOException
    {
        if ( lines == null )
        {
            return;
        }
        if ( lineEnding == null )
        {
            lineEnding = LINE_SEPARATOR;
        }
        for ( Iterator<String> it = lines.iterator(); it.hasNext(); )
        {
            String line = it.next();
            if ( line != null )
            {
                writer.write( line );
            }
            writer.write( lineEnding );
        }
    }

    // copy from InputStream
    // -----------------------------------------------------------------------
    /**
     * Copy bytes from an <code>InputStream</code> to an <code>OutputStream</code>.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * <p>
     * Large streams (over 2GB) will return a bytes copied value of <code>-1</code> after the copy has completed since
     * the correct number of bytes cannot be returned as an int. For large streams use the
     * <code>copyLarge(InputStream, OutputStream)</code> method.
     * 
     * @param input the <code>InputStream</code> to read from
     * @param output the <code>OutputStream</code> to write to
     * @return the number of bytes copied
     * @throws NullPointerException if the input or output is null
     * @throws IOException if an I/O error occurs
     * @throws ArithmeticException if the byte count is too large
     * @since Commons IO 1.1
     */
    public static int copy( InputStream input, OutputStream output )
        throws IOException
    {
        long count = copyLarge( input, output );
        if ( count > Integer.MAX_VALUE )
        {
            return -1;
        }
        return (int) count;
    }

    /**
     * Copy bytes from a large (over 2GB) <code>InputStream</code> to an <code>OutputStream</code>.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * 
     * @param input the <code>InputStream</code> to read from
     * @param output the <code>OutputStream</code> to write to
     * @return the number of bytes copied
     * @throws NullPointerException if the input or output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.3
     */
    public static long copyLarge( InputStream input, OutputStream output )
        throws IOException
    {
        byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
        long count = 0;
        int n = 0;
        while ( -1 != ( n = input.read( buffer ) ) )
        {
            output.write( buffer, 0, n );
            count += n;
        }
        return count;
    }

    /**
     * Copy bytes from an <code>InputStream</code> to chars on a <code>Writer</code> using the default character
     * encoding of the platform.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * <p>
     * This method uses {@link InputStreamReader}.
     * 
     * @param input the <code>InputStream</code> to read from
     * @param output the <code>Writer</code> to write to
     * @throws NullPointerException if the input or output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void copy( InputStream input, Writer output )
        throws IOException
    {
        InputStreamReader in = new InputStreamReader( input );
        copy( in, output );
    }

    /**
     * Copy bytes from an <code>InputStream</code> to chars on a <code>Writer</code> using the specified character
     * encoding.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedInputStream</code>.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * This method uses {@link InputStreamReader}.
     * 
     * @param input the <code>InputStream</code> to read from
     * @param output the <code>Writer</code> to write to
     * @param encoding the encoding to use, null means platform default
     * @throws NullPointerException if the input or output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void copy( InputStream input, Writer output, String encoding )
        throws IOException
    {
        if ( encoding == null )
        {
            copy( input, output );
        }
        else
        {
            InputStreamReader in = new InputStreamReader( input, encoding );
            copy( in, output );
        }
    }

    // copy from Reader
    // -----------------------------------------------------------------------
    /**
     * Copy chars from a <code>Reader</code> to a <code>Writer</code>.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedReader</code>.
     * <p>
     * Large streams (over 2GB) will return a chars copied value of <code>-1</code> after the copy has completed since
     * the correct number of chars cannot be returned as an int. For large streams use the
     * <code>copyLarge(Reader, Writer)</code> method.
     * 
     * @param input the <code>Reader</code> to read from
     * @param output the <code>Writer</code> to write to
     * @return the number of characters copied
     * @throws NullPointerException if the input or output is null
     * @throws IOException if an I/O error occurs
     * @throws ArithmeticException if the character count is too large
     * @since Commons IO 1.1
     */
    public static int copy( Reader input, Writer output )
        throws IOException
    {
        long count = copyLarge( input, output );
        if ( count > Integer.MAX_VALUE )
        {
            return -1;
        }
        return (int) count;
    }

    /**
     * Copy chars from a large (over 2GB) <code>Reader</code> to a <code>Writer</code>.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedReader</code>.
     * 
     * @param input the <code>Reader</code> to read from
     * @param output the <code>Writer</code> to write to
     * @return the number of characters copied
     * @throws NullPointerException if the input or output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.3
     */
    public static long copyLarge( Reader input, Writer output )
        throws IOException
    {
        char[] buffer = new char[DEFAULT_BUFFER_SIZE];
        long count = 0;
        int n = 0;
        while ( -1 != ( n = input.read( buffer ) ) )
        {
            output.write( buffer, 0, n );
            count += n;
        }
        return count;
    }

    /**
     * Copy chars from a <code>Reader</code> to bytes on an <code>OutputStream</code> using the default character
     * encoding of the platform, and calling flush.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedReader</code>.
     * <p>
     * Due to the implementation of OutputStreamWriter, this method performs a flush.
     * <p>
     * This method uses {@link OutputStreamWriter}.
     * 
     * @param input the <code>Reader</code> to read from
     * @param output the <code>OutputStream</code> to write to
     * @throws NullPointerException if the input or output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void copy( Reader input, OutputStream output )
        throws IOException
    {
        OutputStreamWriter out = new OutputStreamWriter( output );
        copy( input, out );
        // XXX Unless anyone is planning on rewriting OutputStreamWriter, we
        // have to flush here.
        out.flush();
    }

    /**
     * Copy chars from a <code>Reader</code> to bytes on an <code>OutputStream</code> using the specified character
     * encoding, and calling flush.
     * <p>
     * This method buffers the input internally, so there is no need to use a <code>BufferedReader</code>.
     * <p>
     * Character encoding names can be found at <a href="http://www.iana.org/assignments/character-sets">IANA</a>.
     * <p>
     * Due to the implementation of OutputStreamWriter, this method performs a flush.
     * <p>
     * This method uses {@link OutputStreamWriter}.
     * 
     * @param input the <code>Reader</code> to read from
     * @param output the <code>OutputStream</code> to write to
     * @param encoding the encoding to use, null means platform default
     * @throws NullPointerException if the input or output is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static void copy( Reader input, OutputStream output, String encoding )
        throws IOException
    {
        if ( encoding == null )
        {
            copy( input, output );
        }
        else
        {
            OutputStreamWriter out = new OutputStreamWriter( output, encoding );
            copy( input, out );
            // XXX Unless anyone is planning on rewriting OutputStreamWriter,
            // we have to flush here.
            out.flush();
        }
    }

    // content equals
    // -----------------------------------------------------------------------
    /**
     * Compare the contents of two Streams to determine if they are equal or not.
     * <p>
     * This method buffers the input internally using <code>BufferedInputStream</code> if they are not already buffered.
     * 
     * @param input1 the first stream
     * @param input2 the second stream
     * @return true if the content of the streams are equal or they both don't exist, false otherwise
     * @throws NullPointerException if either input is null
     * @throws IOException if an I/O error occurs
     */
    public static boolean contentEquals( InputStream input1, InputStream input2 )
        throws IOException
    {
        if ( !( input1 instanceof BufferedInputStream ) )
        {
            input1 = new BufferedInputStream( input1 );
        }
        if ( !( input2 instanceof BufferedInputStream ) )
        {
            input2 = new BufferedInputStream( input2 );
        }

        int ch = input1.read();
        while ( -1 != ch )
        {
            int ch2 = input2.read();
            if ( ch != ch2 )
            {
                return false;
            }
            ch = input1.read();
        }

        int ch2 = input2.read();
        return ( ch2 == -1 );
    }

    /**
     * Compare the contents of two Readers to determine if they are equal or not.
     * <p>
     * This method buffers the input internally using <code>BufferedReader</code> if they are not already buffered.
     * 
     * @param input1 the first reader
     * @param input2 the second reader
     * @return true if the content of the readers are equal or they both don't exist, false otherwise
     * @throws NullPointerException if either input is null
     * @throws IOException if an I/O error occurs
     * @since Commons IO 1.1
     */
    public static boolean contentEquals( Reader input1, Reader input2 )
        throws IOException
    {
        if ( !( input1 instanceof BufferedReader ) )
        {
            input1 = new BufferedReader( input1 );
        }
        if ( !( input2 instanceof BufferedReader ) )
        {
            input2 = new BufferedReader( input2 );
        }

        int ch = input1.read();
        while ( -1 != ch )
        {
            int ch2 = input2.read();
            if ( ch != ch2 )
            {
                return false;
            }
            ch = input1.read();
        }

        int ch2 = input2.read();
        return ( ch2 == -1 );
    }

}
